I just moved into a home built in 1955. During inspection, it was noted that none of the outlets were grounded even though they had three prong outlets installed.

Per our agreement, the owner supposedly grounded all the sockets using a licensed electrician. During our final walk through, the owner's general handy man told us he rewired everything. I unfortunately didn't think anything of it.

Come to move in day. The cable installer shows up. When plugging the HDMI cable into the TV, the cable box sparks and catches fire and the TV is dead. Scorched and melted HDMI ports on both end.

The cable installer assumes a bad box, gives me a new box. We try again with new everything (cable box, power cords, HDMI cable, TV). This time we notice the HDMI sparks like mad when making contact with the HDMI port in the TV. Luckily we were wary this time and didn't actually plug the cable in.

At this point I'm suspecting the "unhandy" man botched the grounding on the outlets. I'm getting an electrician out here Monday to take a look. Right now I'm avoiding plugging anything in with a three prong power cord.

It's impossible to say what he actually did. I suspect he simply put ground tails to the boxes, but the boxes are not grounded either. Not sure what specifically would cause such violent sparking. One source obviously has voltage and is looking for a path back to it's source. I would say that current flow is killing your electronics. And whatever "fire" or smoke you saw was simply electronic components frying.
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Speedy PeteyFeb 16 '14 at 12:43

Not that there's any excuse for this sort of "grounding" but in the handyman's defense it looks like that outlet has the hot and neutral swapped also. Hot (black wire) should be the smaller blade. That may have led to the confusion. BTW I hope you are sending all of your electric & TV repair bills to the former owner with a note saying he's lucky there isn't an accompanying wrongful death lawsuit.
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Henry JacksonFeb 17 '14 at 19:53

3

WTF!? I'm not normally in favor of a sue-happy culture, but I think this is one of the times where contacting a lawyer is called for. Everyone makes mistakes, but this is pure negligence. For the safety of you and others, that electrician should never be allowed to wire another house again!
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BlueRaja - Danny PflughoeftFeb 19 '14 at 20:10

2

I'd bring in a real electrician to check everything that the "handyman" might have touched. It's clear from the photos that he knows nothing about electrical wiring. Aside from the obvious hot to ground problem, he's put two wires on a single screw terminal, and bridged the two terminals with wire for some reason, even though the breakoff tab is still there. It's as if he thought that all the screw terminals had to be used. Also he didn't wrap the wires clockwise around the terminals.
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JohnnyFeb 19 '14 at 21:45

4 Answers
4

Adding a proper ground to every receptacle in the house is no small feat, it's weird that the handyman just casually mentioned that he did it. I believe the only correct way to do it would be to run a new ground wire of the proper size back to the service panel where it can be connected to the grounding rods.

Perhaps the handy man just used pigtails to ground to the box, as @SpeedyPetey says. Or maybe he connected the ground to the neutral, which would be good enough to fool an outlet tester. Or maybe he accidentally connected the ground to the hot side, which might explain your sparks. (Many appliances have their metal housing connected to ground. If the exterior of one of your appliances was actually electrified that would explain the sparks.)

If you have a simple outlet tester you could start with that, but it will not detect all faulty conditions like a ground / neutral swap or connection. You could also shut the power off and pull one of the receptacles off the wall, to see if you can tell what kind of grounding, if any, is actually there.

I suspect you will want to get an electrician and your real estate agent involved.

Realtor and original contractor are already involved. I still want to get a second opinion from a third party plus I need a quote for a whole hour surge protector anyway. I have a socket tester, but it's the $10 variety so it's says everything is fine that's not saying much.
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JuiceFeb 16 '14 at 15:38

OK, if all the outlets check out OK with the tester, try these things: 1) turn off the power and unscrew the outlet you were using with the TV/cable box. The ground wire should be bare copper. Is there one? Where does it go? 2) Go to your service panel and take the cover off. Look for the newly-installed copper grounding connectors. Are they present? They should be attached to the same metal bus bar as the white neutral wires.
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Henry JacksonFeb 16 '14 at 16:45

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Note that under normal circumstances you can take the cover plate off an outlet without any risk, but in this case there is suspicion that the ground itself may be hot, so I would cut power to that circuit before touching anything.
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Henry JacksonFeb 16 '14 at 16:47

See my edit above with pictures. The guy wired hot to the ground.
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JuiceFeb 17 '14 at 14:14

If you have an ungrounded system, the only safe and legal way of grounding it is to run all new cables.

I have come across outlets that had a "fake ground", that is where the neutral is also connected to the ground screw. If the hot and neutral wires were swapped, which can easily happen on old cloth wiring where the white color has fallen off the neutral, you would see the exact problem you have.

I have also seen it where the hot wire has shorted to the ungrounded metal box, which the outlet was then swapped to one that has a ground pin. Which could also cause the problems you are seeing.

To ground them properly would have likely required putting holes in the walls. The reason being that all of the cables supplying those outlets would need to be replaced. The only way to get around doing that is to put in outlets that don't have a ground pin, or to put in GFCI outlets.

As an aside it is very unlikely to find a handy-man that could fix this situation that quickly, and do so properly.

Use a non-contact voltage detector pen to check the ground screw/strap of each outlet -- if hot is present on the outlet ground terminal (i.e. the reverse polarity bootleg ground that has been alluded to by other answers), it will light up brightly and/or beep at you as soon as you put it near the hot outlet ground strap; on a properly wired outlet, you'll need to stick the tip in the hot slot. See this article for more details on the problem you may have.

Are simple voltmeter will answer the question. At the outlet the TV is plugged into measure across the two prong holes, and then from each to the ground prong hole. There should be 120V from the narrow prong hole to the other two, and 0V from the wide prong socket to the ground hole. Any deviation from that indicates a problem with the AC wiring. If that appears OK then, and be very careful doing this, measure from the wide prong to a ground, such as the shield of the coax that should be grounded to Earth ground. If there is more than trace voltage between them then the coax may not be properly grounded.

Did you have the house inspected by a certified inspector? Everyone I have used in the past few years has tested every outlet. If you did have it inspected and they did not do that, then you may have a case against them.